A test method for predicting the cycle performance of pouch batteries

Abstract

The invention discloses a test method for predicting the cycle performance of pouch batteries, comprising the following steps: S1, taking m standard pouch batteries, discharging the standard pouch batteries to empty, and standing still to balance the temperature of the standard pouch batteries; Then adjust the initial binding force F0 to fix the standard pouch battery in the expansion force test device, then conduct cycle performance test on the standard pouch battery, and detect the expansion force of the standard pouch battery during the cycle, where the number of cycles is N, the expansion force of the standard pouch battery at 100 cycles per cycle is recorded as F; S2, the calculation of the expansion force change rate takes the cycle number N as the abscissa, and the expansion force change rate △F% as the ordinate to obtain m strips N‑ △F% standard curve; S3, take the pouch battery to be tested and obtain the N-△F% curve of the pouch battery to be tested according to the operation in S1 and S2; S4, compare the N-△F% curve of the pouch battery to be tested with Comparison of m N-△F% standard curves.

Description

technical field [0001] The invention relates to the technical field of pouch batteries, in particular to a test method for predicting cycle performance of pouch batteries. Background technique [0002] Cycle life is the most important indicator to evaluate the performance of a lithium-ion battery. With the continuous expansion of the application range of power batteries, car companies have increased the cycle life requirements of batteries to more than 2,000 weeks. [0003] There are many factors that lead to the attenuation of lithium-ion batteries, such as: the precipitation of metal lithium, the growth of SEI film, the side reaction between positive and negative electrode materials and electrolyte, the consumption of electrolyte, the blockage or damage of diaphragm, etc., so developers need to comprehensively consider Based on the above factors, the DOE experiment was carried out to screen out the performance-standard battery system, but the DOE experiment involves a seri...

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Problems solved by technology

[0003] There are many factors that lead to the attenuation of lithium-ion batteries, such as: the precipitation of metal lithium, the growth of SEI film, the side reaction between positive and negative electrode materials and electrolyte, electrolyte consumption, diaphragm blockage or damage, etc., so developers need to take comprehensive consideration Based on the above factors, the DOE experiment was carried out to screen out the performance-standard battery system, but the DOE experiment involves a series of variable factors that need to evaluate multiple batteries at the same time and the test cycle is long, which takes up a lot of test resources. Therefore, it is urgent to find a new evaluation method. Shorten the evaluation period

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